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At least 19 recordsLinked to original sources

PubMed1988

Altered proteoglycans in cultured human retinitis pigmentosa retinal pigment epithelium.

Proteoglycans are involved in a variety of cell-cell and cell-matrix interactions. These include cell adhesion, growth regulation and a number of developmental processes. Their involvement in such interactions may be of particular importance in retinitis pigmentosa (RP) because of the detachment and migration of retinal pigment epithelial (RPE) cells often associated with this condition. Because of these important functions in cell behavior, we have been studying the proteoglycans produced by human RPE and how these may be altered in RP. Confluent cultures of RPE from normal donors and from two donors with dominantly inherited RP were labeled with 3H-glucosamine and 35SO4 and the proteoglycans isolated from the medium, substratum and two cell membrane-associated compartments, designated "EDTA-released" and "cell-associated." The proteoglycans were analyzed for size distribution by Sepharose CL-4B chromatography and for glycosaminoglycan (GAG) composition based on enzymatic and chemical susceptibilities. Differences in size distribution and GAG composition were found between the two cell-associated compartments on normal cells. Retinitis pigmentosa proteoglycans differed from their normal counterparts in corresponding compartments both in size distribution and GAG composition. Most affected were those proteoglycans released from the cell surface by EDTA. These findings may be of importance in retinitis pigmentosa since alterations in these molecules could influence the way RPE cells interact with their microenvironment.

Adult↗

PubMed1987

Altered glycoconjugates in cultures of retinitis pigmentosa retinal pigment epithelium.

These studies have shown that these are some alterations in the complex carbohydrates associated with the cell surface of RPE cells from donors with dominant retinitis pigmentosa. Differences are found both in proteoglycans and in glycoproteins. Proteoglycans of different sizes and glycosaminoglycan composition are associated with distinct cellular compartments of normal RPE cells. In the case of dominant retinitis pigmentosa studied here, there are some alterations in RPE proteoglycans. Within a given cellular compartment, there may be differences in the size distribution and/or the ratios of the proteoglycan size classes. In addition, there may be altered glycosaminoglycan content found between peaks of comparable size. There also appears to be more microheterogenity in oligosaccharides derived from surface glycoproteins of retinitis pigmentosa RPE cells. This may be due to differences in the total number of carbohydrate units or in the organization of the branching structure as suggested by altered size distribution and lectin-reactivity, respectively. While the reason for these differences is not clear, they could be due to abnormal processing and/or increased degradation. Considering their importance, alterations in cell surface glycoconjugates could affect the ability of RPE cells to interact with their environment and to maintain a healthy status.

Adult↗

PubMed2005

[The characteristics of retinitis pigmentosa with retinal vascular occlusion].

OBJECTIVE: To observe clinical features of Retinitis pigmentosa with retinal vascular occlusion and its prognosis. METHODS: To analyze the clinical Data in 18 cases retrospectively using fundus examination, fundus fluorescein angiography, indocyanine green angiography, electroretinogram, visually evoked potential etc. Gene screening was performed in 3 cases. RESULTS: the major clinical manifestations of the disease were optic atrophy, vascular attenuation to obliteration, widespread retinal pigment epithelium atrophy with depigmentation and/or fine pigment spots, total or nearly total a and b wave were extinct in the examination of electroretinogram. All this manifestations were compatible with that of typical Retinitis Pigmentosa (tapeto-retinal dystrophy). It also had its unique features, such as total or nearly total vascular obliteration, marked optic atrophy in later stage, and choroidal vessels abnormal. Gene mutation was not found in gene encoding area of RHO gene of No: 3 chromosome and of RLBPI gene of No: 15 chromosome. vision loss in this kind retinitis pigmentosa is much faster than that of typical retinitis pigmentosa. CONCLUSION: Retinitis pigmentosa with retinal vascular occlusion may belonged to a kind of tapeto-retinal dystrophy, vascular progressive obliteration was probably its associated disease.

Adolescent↗

PubMed1988

Clinical and serum lipid findings in a large family with autosomal dominant retinitis pigmentosa.

Retinitis pigmentosa, of unknown cause, has recently been associated with decreased amounts of the polyunsaturated fatty acid, docosahexaenoic acid, in the plasma of affected as compared with unaffected relatives. It has been suggested that this finding may serve as a marker for the disease and might indicate alterations in photoreceptor cell metabolism. The authors studied 54 members of a family with dominantly inherited retinitis pigmentosa in five generations. In addition to the typical clinical findings of retinitis pigmentosa, eight persons also had a bull's eye maculopathy, and four persons had uni- or bilateral optic nerve drusen. When the authors determined the plasma fatty acid and lipid contents, they saw the expected age-related effect on cholesterol and triglycerides, but an unexpected, significant reduction in fatty acids in the unaffected controls as compared with persons with retinitis pigmentosa. The authors' results emphasize the heterogeneity of phenotypic expression of retinitis pigmentosa within a single family.

Adolescent↗

PubMed1982

Investigation of retinitis pigmentosa.

Retinitis pigmentosa is a solitary manifestation of separate genetically determined disorders in which there is progressive loss of vision and the appearance of characteristic fundus abnormalities. It is likely that each disease contained within this family of disorders has a different aetiology, a consideration which is important to the clinician, the researcher and the therapist. To the clinician it is essential to be able to identify the inheritance of the disorder in order to give educated genetic advice. It is the responsibility of the clinician to sub-divide retinitis pigmentosa into purer samples of disease since without such a sub-division research is unlikely to be fruitful. It is unreasonable to expect a biochemist to define systemic biochemical abnormalities if blood is analysed from a series of patients, each of which has a different disorder. If the cause of retinal degeneration in an animal homologue of human retinitis pigmentosa is identified the question is then raised as to whether the abnormality is relevant to human disease and, if so, to which one. Moreover, if a metabolic abnormality is identified in one disease it will not necessarily to be found in others and similarly, if therapy is effective in one form of the disease it may not be effective for all patients. A sub-division of retinitis pigmentosa may be made on the basis of inheritance of the disorder, on the basis of morphologic changes in the fundus, and on the qualitative functional changes identified. Such observations may also give some clues as to the pathogenesis of the different forms of RP or at least indicate in which cell system the primary disorders lie and will also show in what way the defect interferes with cell function. In this paper it is hoped to show that studies undertaken by the various disciplines within ophthalmology have now made limited achievements towards the goals of subdividing retinitis pigmentosa (RP) into purer samples of disease and typifying the functional and morphological attributes of the constituent disorders.

Dark Adaptation↗

PubMedDate not supplied

Retinitis pigmentosa.

Retinitis pigmentosa is a clinically and genetically heterogeneous group of hereditary disorders in which there is progressive loss of photoreceptor and pigment epithelial function. The prevalence of retinitis pigmentosa is between 1/3000 and 1/5000 making it one of the most common causes of visual impairment in all age groups. The natural history, differential diagnosis, diagnostic clinical and electrophysiologic findings are reviewed. Generalization about the different genetic subtypes of retinitis pigmentosa are reviewed along with the uses of DNA probes for linkage studies. Syndromes in which retinitis pigmentosa is a manifestation are summarized.

Cross-Sectional Studies↗

PubMed1996

HLA typing and retinitis pigmentosa.

Retinitis pigmentosa is a disease whose pathogenesis remains largely obscure. A lot of evidences support the hypothesis that auto-immunity is involved, but no HLA antigen has ever been associated with retinitis pigmentosa. Ten patients with autosomal recessive retinitis pigmentosa were tissue typed for class I and II HLA antigens. The results of the study show a significant increase in the frequency of the antigens Cw4, Cw6 and DR11. High values of relative risk were found also for some class I antigens, but the size of the group of patients with these loci precluded a meaningful statistical analysis.

Adolescent↗

PubMed1993

[A molecular biological study on retinitis pigmentosa].

Retinitis pigmentosa was investigated with molecular genetic techniques, to identify gene abnormalities and to obtain a better understanding of the mechanism of retinal degeneration. First, a search for candidate genes was performed focusing on rhodopsin, peripherin/RDS, and phosducin genes, using non-radioisotopic SSCP and genomic DNA samples obtained from 387 Japanese patients with retinitis pigmentosa, including 56 families of the autosomal dominant type (ADRP). One ADRP family with rhodopsin Pro-347-Leu mutation and another with peripherin/RDS Asn-244-Lys mutation were identified. The genotype and phenotype correlation of each ADRP family was then analysed. Ocular findings associated with the rhodopsin Pro-347-Leu in the Japanese family were similar to those reported in Caucasian families, indicating that the same mutation can produce the common phenotype even among different ethnic populations. The phenotype associated with the peripherin/RDS Asn-244-Lys showed typical findings of retinitis pigmentosa associated with bull's-eye maculopathy. Finally, glutamate was immunohistochemically quantified in the photoreceptor inner segment of rds/rds mice using anti-Glu antibody. The results showed that glutamate was accumulated in the rds/rds mouse photoreceptor inner segment, suggesting that glutamate may play a role in the process of retinal degeneration caused by the peripherin/RDS gene abnormality, although the precise mechanism is currently unknown.

Animals↗

PubMed2001

Mutations P51U and G122E in retinal transcription factor NRL associated with autosomal dominant and sporadic retinitis pigmentosa.

Retinitis pigmentosa (RP) is the most frequent form of inherited retinopathy. RP is genetically heterogeneous with autosomal dominant, autosomal recessive and X-linked forms. Autosomal dominant retinitis pigmentosa (adRP) accounts for about 20-25% of all RP cases. At least ten adRP loci have so far been mapped. However, mutations causing adRP have been identified only in four retina-specific genes: RHO (encoding rhodopsin) in approximately 20% of adRP families, peripherin/RDS (3-5% of adRP) and recently RP1 (Pierce et al., 1999, Sulivan et al., 1999) and NRL gene. Only one mutation in the NRL gene causing adRP has so far been reported (Bessant et al., 1999). Here we report a novel mutation Pro51Leu in an adRP Spanish family supporting that mutation in NRL is the cause of adRP. A second missense mutation Gly122Glu has been observed in a simplex RP patient that may represent a sporadic case of retinitis pigmentosa. Hum Mutat 17:520, 2001.

Base Sequence↗

PubMed2001

Update on the molecular genetics of retinitis pigmentosa.

Retinitis pigmentosa (RP) is a heterogeneous group of retinal dystrophies characterized by photoreceptor cell degeneration. RP causes night blindness, a gradual loss of peripheral visual fields, and eventual loss of central vision. Advances in molecular genetics have provided new insights into the genes responsible and the pathogenic mechanisms of RP. The genetics of RP is complex, and the disease can be inherited in autosomal dominant, recessive, X-linked, or digenic modes. Twenty-six causative genes have been identified or cloned for RP, and an additional fourteen genes have been mapped, but not yet identified. Eight autosomal dominant forms are due to mutations in RHO on chromosome 3q21-24, RDS on 6p21.1-cen, RP1 on 8p11-21, RGR on 10q23, ROM1 on 11q13, NRL on 14q11.1-11.2, CRX on 19q13.3, and PRKCG on 19q13.4. Autosomal recessive genes include RPE65 on chromosome 1p31, ABCA4 on 1p21-13, CRB1 on 1q31-32.1, USH2A on 1q41, MERTK on 2q14.1, SAG on 2q37.1, RHO on 3q21-24, PDE6B on 4p16.3, CNGA1 on 4p14-q13, PDE6A on 5q31.2-34, TULP1 on 6p21.3, RGR on 10q, NR2E3 on 15q23, and RLBP1 on 15q26. For X-linked RP, two genes, RP2 and RP3 (RPGR), have been cloned. Moreover, heterozygous mutations in ROM1 on 11q13, in combination with heterozygous mutations in RDS on 6p21.1-cen, cause digenic RP (the two-locus mechanism). These exciting molecular discoveries have defined the genetic pathways underlying the pathogenesis of retinitis pigmentosa, and have raised the hope of genetic testing for RP and the development of new avenues for therapy.

Chromosome Mapping↗

PubMed1999

Mutations in the RP1 gene causing autosomal dominant retinitis pigmentosa.

Retinitis pigmentosa is a genetically heterogeneous form of retinal degeneration that affects approximately 1 in 3500 people worldwide. Recently we identified the gene responsible for the RP1 form of autosomal dominant retinitis pigmentosa (adRP) at 8q11-12 and found two different nonsense mutations in three families previously mapped to 8q. The RP1 gene is an unusually large protein, 2156 amino acids in length, but is comprised of four exons only. To determine the frequency and range of mutations in RP1 we screened probands from 56 large adRP families for mutations in the entire gene. After preliminary results indicated that mutations seem to cluster in a 442 nucleotide segment of exon 4, an additional 194 probands with adRP and 409 probands with other degenerative retinal diseases were tested for mutations in this region alone. We identified eight different disease-causing mutations in 17 of the 250 adRP probands tested. All of these mutations are either nonsense or frameshift mutations and lead to a severely truncated protein. Two of the eight different mutations, Arg677X and a 5 bp deletion of nucleotides 2280-2284, were reported previously, while the remaining six mutations are novel. We also identified two rare missense changes in two other families, one new polymorphic amino acid substitution, one silent substitution and a rare variant in the 5'-untranslated region that is not associated with disease. Based on this study, mutations in RP1 appear to cause at least 7% (17/250) of adRP. The 5 bp deletion of nucleotides 2280-2284 and the Arg677X nonsense mutation account for 59% (10/17) of these mutations. Further studies will determine whether missense changes in the RP1 gene are associated with disease, whether mutations in other regions of RP1 can cause forms of retinal disease other than adRP and whether the background variation in either the mutated or wild-type RP1 allele plays a role in the disease phenotype.

Adult↗

PubMed2005

Mutation screening of three candidate genes, ELOVL5, SMAP1 and GLULD1 in autosomal recessive retinitis pigmentosa.

Retinitis pigmentosa (RP) is the most common form of retinal dystrophy. It is featured by a great clinical and genetic heterogeneity. Different patterns of inheritance exist, such as autosomal dominant and recessive, X-linked and digenic. RP25, a locus for autosomal recessive retinitis pigmentosa (arRP), the most frequently inherited form of RP, was mapped to chromosome 6q between D6S257 and D6S1644 microsatellite markers. ELOVL5, SMAP1 and GLULD1 were selected on the basis of their location, tissue expression and/or function. ELOVL5 is implicated in the elongation of long chain fatty acids, including docosahexanoic acid (DHA), which constitutes 50% of the fatty acids of the outer segment of the photoreceptor. SMAP1 (stromal membrane associated protein 1) was found to be located within RP25 locus and is expressed in retina. GLULD1, glutamate-ammonia ligase (glutamine synthase) domain containing 1, plays a key role in the uptake and metabolism of glutamate in the retina. The absence of pathogenic mutations after molecular analysis argues against the implication of ELOVL5, SMAP1 and GLULD1 in the development of RP25 phenotype. Nevertheless, we could not rule them out as good candidates for other retinal degeneration mapping to the same chromosomal region.

Acetyltransferases↗

PubMedDate not supplied

Retinitis pigmentosa.

Retinitis pigmentosa is a subset of inherited diseases associated with progressive degeneration of the retina otherwise classified as retinal dystrophies. Clinically, patients have nyctalopia (night blindness), progressive visual field loss, and eventually loss of central vision. Patients with retinitis pigmentosa should be evaluated for other ocular conditions that may simulate the condition, as well as for systemic disorders.

Humans↗

PubMed2004

Bone marrow-derived stem cells preserve cone vision in retinitis pigmentosa.

Retinitis pigmentosa is a heritable group of blinding diseases resulting from loss of photoreceptors, primarily rods and secondarily cones, that mediate central vision. Loss of retinal vasculature is a presumed metabolic consequence of photoreceptor degeneration. A new study shows that autologous bone marrow-derived lineage-negative hematopoietic stem cells, which incorporate into the degenerating blood vessels in two murine models of retinitis pigmentosa, rd1 and rd10, prevent cone loss. The use of autologous bone marrow might avoid problems with rejection while preserving central cone vision in a wide variety of genetically disparate retinal degenerative diseases.

Animals↗

PubMed1997

Severe manifestations in carrier females in X linked retinitis pigmentosa.

Retinitis pigmentosa (RP) is a group of progressive hereditary disorders of the retina in which various modes of inheritance have been described. Here, we report on X linked RP in nine families with constant and severe expression in carrier females. In our series, however, the phenotype was milder and delayed in carrier females compared to hemizygous males. This form of X linked RP could be regarded therefore as partially dominant. The disease gene maps to chromosome Xp2.1 in the genetic interval encompassing the RP3 locus (Zmax=13.71 at the DXS1100 locus). Single strand conformation polymorphism and direct sequence analysis of the retinitis pigmentosa GTPase regulator (RPGR) gene, which accounts for RP3, failed to detect any mutation in our families. Future advances in the identification of X linked RP genes will hopefully help to elucidate the molecular basis of this X linked dominant RP.

Adolescent↗

PubMed2002

[A new study progress of molecular genetics in autosomal dominant retinitis pigmentosa].

Retinitis pigmentosa (RP) describes a genetically and clinically heterogeneous group of disorders that are characterized by gradual degeneration of photoreceptor cells. Common clinical features include a progressive loss of night vision,leading to night blindness and peripheral-visual-field loss. At least 12 loci have been mapped to chromosomes, and mutations in an ever increasing number of genes have been found to cause autosomal dominant retinitis pigmentosa (ADRP). Six of the 12 genes known to cause ADRP have been cloned. New progress has been made on the studies of structure, mutation and function of these genes.

English Abstract↗

PubMed1994

Abnormal plasma lipids of patients with Retinitis pigmentosa.

Retinitis pigmentosa (RP) is a hereditary retinal degeneration of unknown etiology, resulting in progressive night blindness, loss of peripheral vision, abnormal retinal pigmentation and reduced electroretinographic response. Docosahexaenoic acid (22:6 omega 3) is found in high concentration in the rod outer segment membranes of the retina. Previous reports of low 22:6 omega 3 in blood lipids or phospholipids in RP patients prompted us to evaluate the complete fatty acid (FA) profiles of plasma phospholipids (PL), cholesteryl esters, triglycerides (TG) and nonesterified fatty acids (NEFA) in ten patients with RP. In the PL fraction, we found significantly depressed levels of 22:6 omega 3, 22:5 omega 3, total omega 3, 22:5 omega 6, 22:4 omega 6 and total omega 6 polyunsaturated FA (PUFA), and elevated total saturated acids. Plasma TG showed normal levels of PUFA, normal total saturated FA and total monounsaturated FA. The NEFA fraction showed significant elevation in total saturated FA with depressed total omega 6 PUFA. Evidence is accumulating mulating that RP is associated with abnormal PUFA and lipid metabolism.

Cholesterol Esters↗

PubMedDate not supplied

Plasma levels of endothelin-1 in retinitis pigmentosa.

Retinitis pigmentosa (RP) is an inherited retinal disorder clinically characterized by a pale, waxy optic nerve head, attenuated retinal blood vessels and bone spicule pigment in the retina. Hemodynamic studies have demonstrated that RP is associated with a reduction in the retinal and choroidal blood flow. Retinal hemodynamic impairment is also present in the early stages of RP and various hypotheses have been advanced as to its cause. The authors studied 20 patients, 12 males and 8 females, aged between 26 and 42 years (mean 34.6 years) affected by simplex RP. The twenty patients were divided in two groups according to the degree of sight impairment: group A consisted of 10 patients with a visual acuity of 0.3 +/- 0.1, visual field mean defect 18.988 +/- 3.419 dB and b-wave electroretinogram amplitude of 13.14 +/- 0.308 microV. Group B consisted of 10 patients with a visual acuity of 0.8 +/- 0.2, visual field MD 10.523 +/- 3.582 dB and b-wave electroretinogram amplitude of 26.000 +/- 0.757 microV. An increase in plasma levels of endothelin-1 (ET-1) was found as compared with healthy controls: 1.910 +/- 0.617 pg/ml vs. 1.180 +/- 0.210 pg/ml (p < 0.021), but there was no statistical difference between group A and B (p < 0.163). It is thought that an increase in ET-1 and retinal oxygen levels in RP could lead to vasoconstriction and a decrease in the retinal blood flow worsening the abiotrophic process.

Adult↗